Project setup best practices

[britter]

This PR introduces the best practices defined by the sbt/sbt-fresh plugin. In particular after this change:

• all dependencies will be managed in project/Dependencies.scala
• the build configuration will be managed in project/Build.scala
• the build will use:
  • the sbt/sbt-header plugin for adding the Apache License header to all scala files
  • the sbt/sbt-git plugin for defining the project version
  • the sbt/sbt-scalariform plugin for formatting the source code.

The sbt-git plugin configuration uses the following rules:

• if the currently checked out HEAD is also a git tag, and the working copy is not dirty, the version will be extracted from the tag name
• if the currently checked out HEAD is also a git tag, and the working copy is dirty, the version will be tagname-SNAPSHOT
• if the currenlty checked out HEAD is not a git tag, the version will be lastTagName-numberOfCommitsSinceLastTag-gitHash

Hope you like it! :-)

[bripkens]

Wow, thanks for the PR, mate :)!

[bripkens]

LGTM, thanks :+1: